Chandler Carruth 44a1385c45 [LPM] Teach the legacy pass manager to support *using* an analysis ... without *requiring* it. This allows a pass indicate that it will use an analysis if available (through getAnalysisIfAvailable). When the pass manager knows this, it will refrain from deleting that analysis if it can. Naturally, it will still get invalidated at the correct time. These passes are not considered when scheduling the pass pipeline, so typically they will require manual scheduling, but this may also allow passes with getAnalysisIfAvailable to find the analysis more often if nothing after them requires that analysis and it wasn't invalidated. I don't have a particular use case with the current passes, but with my new structure for alias analyses, this will be very useful. We want to allow people to customize the set of AAs available by scheduling additional passes. These's aren't ever *required* for obvious reasons. So we need some way to mark in the legacy pass manager that they will still be used if available. This is essentially how analysis groups already work. But this makes the feature generally available and more explicit. It should allow the AA change to not impact how people trigger a custom alias analysis being available at a certain point in compilation. Differential Revision: http://reviews.llvm.org/D12114 llvm-svn: 245409		2015-08-19 03:02:12 +00:00
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llvm	[LPM] Teach the legacy pass manager to support *using* an analysis	2015-08-19 03:02:12 +00:00
llvm-c	[IR] Add token types	2015-08-14 05:09:07 +00:00